Three-dimensional printer



FIG. 1 is a perspective view of a three-dimensional printer showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side view thereof;

FIG. 5 is a right side view thereof; and,

FIG. 6 is a top plan view thereof.

The broken lines are for illustrative purposes only and form no part of the claimed design. The diagonal lines indicate transparency. 

CLAIM The ornamental design for a three-dimensional printer, as shown and described. 